An object detecting apparatus is known which detects a relative speed of a nearby object, calculates a relative acceleration using the relative speed, and then executes various types of control tasks based on the relative acceleration. For instance, Japanese Patent First Publication No. 2011-121491 teaches such a type of object detecting apparatus which detects a relative speed of an own vehicle to another vehicle, time-differentiates the relative speed to derive a relative acceleration, calculates a time-to-collision that is a period of time it takes for the relative distance between the own vehicle and another vehicle to reach zero, and then perform a driver-assistance task based on the time-to-collision.